Process for producing fibers



Patented Sept. 8, 1970 U.S. Cl. 264-210 5 Claims ABSTRACT OF THEDISCLOSURE Novel polyamide fibers of trans-1,4-cyclohexanedicarboxylicacid, terephthalic acid and 3,3-ethylenedioxybis- (propylamine) in amolar ratio of trans-1,4-cyclohexanedicarboxylic acid terephthalic acid:3,3'-ethylenedioxybis (propylamine) of about 70-100:30-0:100. The novelsynthetic fibers are heat set by a particular technique and possess aunique set of properties. Preparation of the novel synthetic fibers maybe by melt spinning the polyamide at a temperature of at least 290 C.,drawing the resulting fiber to at least three times its original lengthat a temperature of at least about 125 C. and stabilizing the drawnfiber at a temperature of at least about 220 C. while allowing the fiberto relax by at least 3 percent of its drawn length.

The present invention is directed to a process for producing newsynthetic fibers which have unexpectedly soft silk-like hand in fabrics,and to a process for their production. More particularly, the inventionis concerned with the preparation of synthetic fibers from polyamides oftrans-1,4-cyclohexanedicarboxylic acid and 3,3'-ethy1-enedioxybis(propylamine) containing 0-30 mole percent terephthalic acid.

Fibers obtained from the melt spinning of polyamides oftrans-1,4-cyclohexanedicarboxylic acid and3,3-ethylenedioxybis(propylamine) containing 030 percent terephthalicacid present considerable difiiculty in heat setting. For example, aswill be demonstrated below, if one utilizes an elevated temperatureheat-setting operation at constant length, the resulting fibers stillexhibit excessive shrinkage in boiling water (e.g., greater than 15percent), which renders the fibers unsuitable for use in the manufactureof textile apparel. If, on the other hand, one utilizes elevatedtemperature heat-setting with free shrinkage, the resulting fibers stilldo not have sufliciently low boiling-water shrink to be useful forapparel. In addition, if one uses a high enough temperature to efiectsubstantial shrinkage during heat-setting, the fibers suifer seriousloss of tenacity and elongation as a consequence of the heat-setting.

Although drawn or drafted fibers of the polyamides of the invention maybe satisfactorily heat set by short time restrained boiling watertreatment followed by short time unrestrained boiling Water treatment,such a stabilizing process unfortunately turns out to be very diflicultto adapt to continuous commercial operations because the modulus, whichis low in the dry fiber and thus contributes a desirable hand tofabrics, becomes even lower when the fiber is in contact with hot water.Consequently, it becomes very difficult to control yarn tensions in hotwater in order to achieve restrained and unrestrained conditions bypassage of the yarn around rolls.

According to this invention a process has now been discovered which canbe readily adapted to continuous commercial operations and whichprovides melt spun fibers of the polyamide to which the invention isdirected that can be easily heat set. Moreover, the process of theinvention provides novel and unusual fibers having a unique set ofproperties. The novel polyamide fibers of the present invention can becharacterized by a tenacity of at least about 2 grams/denier; anelongation of at least about 20 percent; an elastic modulus of about 25grams/ denier, maximum; a boiling water shrink of about 15 percent,maximum; high elastic recovery, about 100 percent at 10 percentextension and about percent recovery at 15 percent extension; a modulus(when wet) of about 15 grams/denier, maximum; and an inherent viscosity(measured at 25 C. in 60/40 phenol tetrachloroethane) of at least about0.8 (usually up to about 1.4). This set of properties cannot be found inany other fiber currently on the market or described in the prior artand polyamide fibers exhibiting these properties pro duce fabrics ofnovel and desirable properties such as a soft comfortable hand and anunexpectedly silk-like feel. The high elastic recovery of the fiber, forexample, contributes to good snap-back and shape retention in fabrics.Also, the relatively high values of tenacity and elongation make thefibers readily blendable with other fibers now on the market such aspolyesters and acrylics. Other uses for which the novel fibers of thisinvention are particularly well suited include carpets and pile fabricsor synthetic furs.

The novel polyamides of the invention may be prepared by a process whichcomprises melt spinning the polyamide at a temperature of at least about290 C. (usually up to about 320 C.), drawing the resulting fiber to atleast 3 times its original length (usually up to about 6 times itsoriginal length), at a temperature of at least about 125 C. (usually upto about 250 C.), and stabilizing the drawn fiber at a temperature of atleast about 220 C. (usually up to about say 260 C.) while allowing thefiber to relax by at least about 3 percent (usually up to about 30percent) of its drawn length. In a preferred embodiment the polyamidesare melt spun at a temperature of from about 290 C. to 310 C. with theresulting fiber then being drawn four to five times its original lengthat a temperature of 200 to 250 C. The drawn fiber is then stabilized ata temperature in the range of from about 250 to 260 C. and allowed torelax by about 5 to 20 percent of its drawn length.

The polyamides to which the invention is directed can be obtained bycondensing trans-1,4-cyclohexanedicarboxylic acid and terephthalic acidwith 3,3'-ethylenedioxybis(propylamine) in molar ratios of from /0/100trans-1,4-cyclohexanedicarboxylic acid/terephthalic acid/3,3'-ethylenedioxybis(propylamine) to 70/30/100 trans-1,4-cyclohexanedicarboxylic acid/terephthalic acid/3,3-ethylenedioxybis(propylamine) The preferred polyamides of the inventionare those containing 0-20 mole percent terephthalic acid. Condensationmethods and techniques utilized for the preparation of the polyamides ofthe invention are well known to those skilled in the art, having beenpreviously described in the literature. See, for example, U.S. Pat.2,939,862 to Caldwell and Gilkey, herein incorporated by reference.

The process described above for the preparation of the novel polyamidesof the invention can be readily adapted to a continuous operation, forexample, by passing multiple ends of drawn yarn around a set of godetrolls driven at a preselected linear speed X, then into a hightemperature stabilizing oven and then, after emerging from the oven,around another set of godet rolls driven at a speed somewhat less thanX. The speed of the rolls at the output of the stabilizing oven isdetermined by the amount of relaxation desired, and can be calculatedfrom the formula:

Output Speed: l.OP)X

where X=speed of input godet rolls in meters/minute or feet/minute, andP=percentage relaxation desired+l00.

In this way the drafted or drawn yarn can be allowed to relax apredetermined amount during its passage through the elevated temperatureoven. Thus, if the yarn speed on emerging from the drafter, for example,is 25 meters/minute, this is also the speed of the godet rolls at theinput to the stabilizing oven. If, by way of illustration, it is desiredto permit 10 percent relaxation of the yarn during stabilizingtreatment, then the speed of the godet rolls at the output of thestabilizing oven is calculated from the above formula as follows:

Output Speed: (LO- 25 meters/minute =22.5 meters/minute The importanceof the elevated-temperature relaxation step cannot be emphasized enoughbecause yarns produced Without it still retain high boiling-Watershrink, that is, greater than 15 percent usually 25 percent or more,thus making them unsuitable for apparel use because of the highuncontrolled shrinkage that fabrics made from them would undergo insubsequent contact with hot water, as in scouring, dyeing, laundering,etc.

Both continuous filament and staple fiber having the aforementionedproperties can be produced by the practice of the present invention.Such fibers can be readily handled on textile processing equipment forconversion into fabrics. Staple fiber, for example, can be readilycarded and drafted into spun yarn and then woven or knitted, or tuftedinto carpets. Likewise, continuous filament yarn can be readily woven orknitted using standard textile equipment and techniques.

The following examples are included to further illustrate the invention.In all the examples given below the copolyamide or homopolyamide,hereinafter referred to as polymer, is prepared by the followingprepolymersolid-phase process: A solution of the salt in water, (i.e.mole ratios of 10070 trans-1,4-cyclohexanedicarboxylic acid and 0-30terephthalic acid combined with 100 moles ofethylenedioxybis(propylamine)) is fed to a multistage, continuous typereactor. Water of solution and water of reaction are removed at apressure of 150-200 p.s.i. and a temperature of 240-250 C. The resultingprepolymer is then granulated and built up in the solid phase at atemperature of 220-230 C. Inherent viscosities, hereinafter designatedas I.V., are determined on polymer and fiber by a procedure well knownto workers in the field of polymers, in 60/40 phenol/tetrachloroethanesolution at a temperature of 25 C.

EXAMPLES 16 The homopolyamide of trans 1,4 -cyclohexanedicarboxylic acidand 3,3-ethylenedioxybis(propylamine) having an I.V. of 1.4 is melt spunwith a A-inch screw extruder and a spinneret having holes of 0.3-mm.diameter each, at a temperature of 300 C. The melt-spun yarn has an I.V.of 1.1. This yarn is drafted 4.6 times its original length by means ofdifferentially driven godet rolls, in air at 130 C. Drafted yarn samplesare then subjected to various heat-setting treatments and the propertiesof the heat-set yarns are then measured by techniques well known toworkers in the field of fibers. The

results obtained from these measurements are given in Table I.

TABLE I.PROPERTIES on YARNS Elastic Percent Tenacity, Percent modulus,boiling Ex. grams elongrams/ water N 0. Heat-setting denier gationdenier shrink 1 None 2.0 40 15 24 2 5 minutes at 140 CJ. 2. 9 31 17 21 35 minutes at 140 OF. 2.0 35 14 20 4 5minutes at 175 CA. 2. 8 19 21 17 55 minutes at 175 C. 0. 6 5 12 12 6.. 1 minute 2. 7 50 13 0 1 Yarnheatset at constant length (restrained).

2 Yarn heat-set with free shrink (unrestrained).

3 Boiling water at constant length followed by 1 minute boiling waterwith free shrinkage.

EXAMPLES 7 1 0 TABLE II.PROPERTIES 0F YARNS Elastic P ercent Tenacity,Percent modulus, boiling Ex. grams] elongrams] water N o. Heat-settingdenier gation denier shrink 1 Yarn heat-set at constant length(restrained). I I 2 In boiling water at constant length followed by 1minute in boiling water with free shrinkage.

EXAMPLES 11-14 A polymer as in Example 1 but of 1.5 I.V. is melt-spunusing a screw extruder feeding a gear pump which delivered the melt to a-hole spinneret of 0.25-mm. hole diameter. The extruder, grear pump andspinneret are held at 300 C. The yarn I.V. is 1.1. Yarn is drafted, withdifferentially-driven sets of godet rolls, through an air oven of 2-feetlength. After emerging from the drafter, the yarn is passed through asecond hot-air oven of 12- feet length; by adjusting the speeds of theinput and output sets of godet rolls for this oven, the drafted yarn canbe allowed to relax by a predetermined amount. Air temperature in thedrafting oven is 240 C.; that in the stabilizing oven is 260 C.; yarnspeed at the input rolls of the drafter is 5.0 meters/minute and theoutput speed is 25.0 meters/minute so that a draft ratio of 5.0 timesits original length is given to the yarn. Speed of the input rolls tothe relaxing oven is accordingly also 25.0 meters/minute. Relaxingconditions used and properties of the resulting yarns are shown in TableIII on the following page.

TABLE III.PROPERTIES 0F YARNS Amount of per- Elastic Percent cent ofrelaxa- Tenacity, Percent modulus, boiling Example tion in 260 0. grams/elongrams] water Number stabilizing oven denier gation denier shrinkEXAMPLE 15 Filament yarn is produced under the conditions given inExample 14 in Table III above. After drafting, sufficient packages areplied together to give a tow of approximately 25,000 total denier; thistow is passed through a crimper to give approximately 10 crimps/inch,then through a tow dryer at C., after which it is then cut into 2-inchstaple length on rotating staple-cutting wheels. Properties of thisstaple are measured while in both a dry and -wet state, the latter afterimmersing in distilled Water at room temperature for 1 hour. Propertiesobtained from these tests are listed in Table IV.

TABLE IV.PROPERTIES OF 4.5 DENIER/FILAMENT, 2- INCH HOMOPOLYAMIDE STAPLEDry 1 (aver- Wet (aver age of 30 age of 30 measurements) measuremen s)Denier 4. 5 Tenacity, grams/denier- 3. 3 1. 8 Elongation, percent 52. 038. 0 Elastic modulus, grams/denien. 16.0 7.0 Boiling water shrink,percent -3. 0 Elastic recovery, percent:

From 10 percent extension 100. 0 100.0 From percent extension 95. 0 95.0

l Conditioned to standard testing conditions of 70 F.

and 65 percent relative humidity.

EXAMPLE 1 Ten pounds of staple fiber are produced as in Example 15. Thisstaple is made into a lap and carded on a conventionel flat top cardwith metallic Wire doifer and cylinder. Two drawing passes are made on adraw frame at 500 feet/minute and a 1 cotton-count yarn is spun from twoends of 2.00 hank roving on an SZ-S spinning mitted to relax 10 percentduring the stabilizing treatment, and the stabilizing-oven treatment isvaried, as shown in Table VI below. Yarn I.V. is 1.0.

TABLE VL-PROPERTIES 0F YARNS OF COPOLYAMIDE OF 0.85 MOLETRANS-1,4-CYCLOHEXANEDICARBOXYLIO ACID/0.15 MOLE TEREPHTHALIC ACID/1.0MOLE 3,3- ETHYLENEDIOXYBIS(PROPYLAMINE) Temperature of Elastic Percentstabilizing oven Tenacity, Percent modulus, boiling Example for 10percent grams/ elongrams] water Number relaxation denier gation deniershrink 1 Not given any elevated-temperature stabilizing treatment.

EXAMPLES 20-44 TABLE VII.-CONTINUOUS FILAMENT (70/40) HOMOPOLYAMIDE YARNDraft Air temp. Elastic Percent All for 8 per- Tenacity, Percentmodulus, boiling Example temp cent relaxgrams/ elongagrams/ water NumberRatlo ation used denier tion denier shrink TABLE V.PROPERTIES OF 20/1COTTON-COUNT HOMOPOLYAMIDE SPUN YARN It can be seen from the above tablethat temperatures Dly 'Wet Tenacity, grams/denier 2. 0 1. 1 Elongation,percent 32 34 Elastic modulus, grams/denier 9 5 Elastic recovery:

From 5 percent extension, percent. 100 100 From 10 percent extension,percent. 99 99 From 15 percent extension, percent. 95 96 Boiling watershrink, percent 4. 0 4. 0 Shrink in 175 0. air, percent 0 Packages ofthis spun .yarn are then used to knit a circular tube on alaboratorycircular knitting machine. This knit tube is found to have asurprisingly soft and pleasant hand.

EXAMPLES 17-19 up to 220 C. in the heat-relaxing step are no sufficientto reduce the boiling-water shrink in the resulting yarn to less than 15percent whereas, at a heat-relaxing temperature of 260 C., yarn isproduced which has boiling-water shrink of 4-11 percent (Examples 22,25, 28, 31, 34, 36, 38, 40, 42, and 44 above), a satisfactory level fortextile yarns. An indication of the range of drafting conditions usefulin the invention is also shown by the data in the above table, in thatdraft ratios of 4.0 to 5.0 times the yarns original length, at airtemperatures from to 240 C., produced yarn of good tensile properties.

EXAMPLE 45 Packages of 70/40 continuous filament yarn are produced as inExample 42 except that the input draft speed is 8 meters/minute, draftratio is 4.6 times the yarns original length, and 6 percent relaxationis allowed during heat stabilization. Twenty ends of yarn are draftedand heat-stabilzed at a time and wound into separate packges with abouttwo Z-tWists/inch. Packages of 40/27 continuous filament yarn areproduced from the polymer of Example 7 by the following procedure. AneXtruder, gear pump, spinneret unit heated at 290 C. is used formelt-spinning, with a 27/0.3-mm. spinneret being employed. The yarn isdrafted 20 ends at a time, using 8 meters/minute input draft speed, 4.2times its original length draft ratio at 240 C. draft-oven airtemperature, with percent relaxation at 260 C. air temperature in therelaxing oven. Properties of the continuous filament yarns are given inTable VIII.

TABLE VIII.PROPERTIES OF CONTINUOUS FILAMENT HOMOPOLYAMIDE YARN 70/40yarn 40/27 yarn (average of (average of 36 packages) 78 packages)Tenacity, gran1s/denier 3. 2 2. Elongation, pcrcent 36. 0 35. 0 Elasticmodulus, grams/den 17.0 14. 0 Boiling water shrink, percent. 7.0 5. 0 IV 1. 1 0.9

EXAMPLE 46 The polymer of Example 7 is melt-spun into yarn of 1.1 I.V.using an extruder, gear pump, spinneret unit heated at 300 C., with a100/0.3-mm. spinneret being employed. 1.5 denier-filament l /z-inchstaple fiber is produced as in Example except that drafting and relaxingconditions used are those of Example 40 in Table VII. Thirty pounds ofthis staple is then converted into 30/1 cotton-count spun yarn, usingprocessing procedures well known to those skilled in the textile art andsimilar to that described in Example 16 previously. This spun yarn isthen knit on a -cut jersey knitting machine into a fabric which, afterscouring and drying, is sewn into T-shirts. These T-shirts are found tohave a soft hand, and when worn gave a very comfortable, pleasant feelto the wearer. In contrast, T-shirts similarly made from commercial l/z-denier polyester staple fiber are found to impart a clammy,uncomfortable sensation to the wearer.

EMMPLE 47 The copolyamide of Example 17 is melt spun into yarn of I.V.1.1, using an extruder, gear pump, spinneret unit heated at 300 C., witha 50/0.3-mm. spinneret being employed. The melt-spun yarn is then giventhe same drafting and heat-stabilizing treatment as that of Example 18.Small skeins of this yarn are then subjected to the following treatment:(A) scouring for 30 minutes at 90 C. in an aqueous solution of 1 percentIgepon T plus 1 percent tetrasodiumpyrophosphite, dyeing 1 hour at theboil with a commercial premetallized yellow dye, rinsing, scouringagain, and then drying in a 250 F. oven. Samples of yarn after the abovetreatment are then subjected to the following treatments: 1) Hoffmanpressing; (2) Stoddard-solvent dry cleaning, under a procedure specifiedby the AATCC (American Association of Textile Chemists and Colorists);(3) perchloroethylene dry cleaning, under a procedure specified by theAATCC. Skeins are examined after each of the three numbered treatmentsabove and are found to exhibit substantially no evidence of loss in thebright yellow color (obtained after the first treatment A) or of fiberdegradation.

EXAMPLE 48 Yarn is produced under conditions identical to those ofExample 44. Packages of this yarn are used to knit a circular tube on alaboratory knitting machine. A sample of this knit tube is dyed with 3percent Eastman Fast Blue GLF, using standard disperse dye procedure atthe boil with no carrier. The dyed sample is then subjected to 25 cyclesof dry cleaning in perchloroethylene, at the end of which it showed noevidence of color loss or fiber degradation.

EXAMPLE 49 Staple fiber of 15 denier/filament and 6-inch length isproduced by a procedure similar to that described in Example 15, exceptthat in melt spinning the homopolyamide a 100-hole spinneret of 0.45-mm.hole diameter is used. This staple fiber is carded and spun into 2 /2c.c. yarn with 4 Z-twists per inch in the singles and 3 S-twists perinch in the ply, using procedures well known to workers in the textilefield. This spun yarn is then tufted into a 32 ounce/square yard levelloop carpet, again using techniques which are familiar to those skilledin the textile art. This carpet is found to have a surprisingly soft,luxuriant feel with excellent resilience or recovery from crushing.

From the foregoing it can be seen that by practicing this invention onecan produce a line of totally new synthetic fibers from a series ofhomopolyamides and copolyamides. That is, by following the plurality ofprocess steps set forth hereinbefore, novel and unusual fibers areproduced having the following unique set of properties:

Inherent viscosity (measured in 60/40 phenol/tetrachloroethane)--atleast about 0.8 Tenacity, grams/denier-at least about 2 Elongation,percent-at least about 20 Elastic modulus, grams/denier-about 25 maximumBoiling water shrink, percent-about 15 maximum Elastic recovery:

From 10 percent extension, percent-about 100 From 15 percent extension,percentat least about Modulus (when wet), grams/denier-about 15 maximumMoisture absorption, percent-at least 3 As mentioned hereinbefore, thisset of unique properties cannot be found in any other fiber heretoforeknown in the art. Thus fibers of this invention having this set ofproperties are readily formed into fabrics and the like that have noveland highly desirable properties such as, for example, a very soft,comfortable hand with an unexpectedly silk-like feel. Furthermore, thehigh elastic recovery of the novel fibers contributes to good snapbackand shape retention in fabrics while the relatively high values oftenacity and elongation make these fibers readily blendable with otherfibers now on the market. The novel fibers can also be readily convertedinto carpets and pile fabrics which have a soft, luxurious feel withexcellent resilience.

The invention has been described in detail With particular reference topreferred embodiments thereof, but it will be understood that variationsand modifications can be eifected within the spirit and scope of theinvention as described hereinabove and as defined in the appendedclaims.

We claim:

1. A process for the preparation of novel synthetic fibers of polyamidesof trans-1,4-cyclohexanedicarboxylic acid, terephthalic acid and3,3-ethylenedioxybis(propylamine) in a molar ratio oftrans-1,4-cyclohexanedicarboxylic acid terephthalic acid3,3'-ethylenedioxybis (propylamine) of about 70 to :30 to 0:100, thefiber having an inherent viscosity (measured in 60/40phenoltetrachloroethane) of at least 0.8, a tenacity in grams/ denierof, about 2 or more, an elongation of about 20 percent or more, anelastic modulus in grams/denier of about 25 or less, boiling watershrink of about 15% or less, an elastic recovery of 100% from 10%extension, elastic recovery of about 95% or more from 15 extension and amodulus when wet of about 15 grams/denier or less, the processcomprising melt spinning said polyamide at a temperature of at least 290(3., drawing the 9 resulting fiber to at least 3 times its originallength at a temperature of about 125 C. or more and stabilizing thedrawn fiber at a temperature of about 220 C. or more while allowing thefiber to relax by about 3 percent or more of its drawn length.

2. The process of claim 1 wherein the polyamide contains less than 20percent terephthalic acid.

3. The process of claim 1 wherein the molar ratio oftrans-1,4-cyclohexanedicarboxylic acidzterephthalic acid:3,3'-ethylenedioxybis(propylamine) is 852152100.

4. The process of claim 1 wherein the polyamide contains 0 percentterephthalic acid.

5. The process of claim 4 which comprises melt spinning said polyamideat a temperature of between about 290 and 310 0., drawing the resultingfiber to between about 4 to 5 times its original length at a temperatureof between about 200 and 250 C. and stabilizing the drawn fiber at atemperature of between about 240 and 260 C.

while allowing the fiber to relax between about 5 and 20 percent of itsdrawn length.

References Cited UNITED STATES PATENTS 2,130,948 9/1938 Carothers161-179 2,916,475 12/ 1959 Caldwell 26078 2,939,862 6/ 1960 Caldwell26078 X 3,150,435 9/1964 McCol-m et a1. 264346X 3,251,181 5/1966 Breenet a1. 57140 3,321,448 5/1967 Hebler 264-346 X 3,379,809 4/1968 Woods264168 JULIUS FROME, Primary Examiner J. H. WOO, Assistant Examiner US.Cl. X.R. 264235, 342

